neighbors sharing PV charge [RE-wrenches]

[Darryl Thayer]

HI
This came up once before.  I remember several
suggestions.  I have not done this.  I HAVE NOT DONE
THIS. however the one that I liked best was; 

Place a large diode in series with each battery set,
larger that the expected current, ie if you expect the
maximum charge current to be 40 amps place a 100 amp
diode in series with each battery set.  Set the
controller at battery voltage plus 0.7 volts.  Bypass
each diode with a 10 ohm resistor.  The diode prevents
battery dumping one to the other, the diode also
places a slight voltage drop to allow the wire drop to
be overcome.  The wire set to the second battery set
is critical, do not oversize.  If you try this let us
all know how it turns out. 

Another approach and hopfully Outback or RV Power will
answer, would be to increase the array voltage to for
example 120 to 130 volts open circuit.  Then the
distance to the second battery set will not matter as
much.  At the battery-sets use an MPPT such as a MX60
or the RV 4860 AS A bucking DC to DC controller which
will step down the voltage and increase the current. 
Normally you can not parallel the input to these
controls so a capacator accross the input and a diode
in series between the array and capacitor and
controller will prevent the interaction of the pulses
for the controllers.  Outback could test this in a few
days if they get the word.   

Again let us all know how it works.
Daryl

--- Rainshadow <solar at rockisland.com> wrote:
> 
> Howdy wrenches,
> 
> Does anyone have any experience with using a single
> PV array to charge two somewhat distantly separated
> battery banks?  We built a system for a weekend
> cabin up here last year and now the guy's neighbor
> wants to install his own battery and inverter system
> but tie in to the existing array for charging. 
> There is room on the rack to expand to cover both
> their needs and it would be difficult to site a new
> array for neighbor #2.  They are good friends and
> want to share resources.
> 
> I thought about using the C-40 in load control mode
> to float battery #1 and then dump the charging
> current to another C-40 at battery #2.  But it seems
> like there might be a better solution.
> 
> Its a 48V system and the distances are reasonable,
> so voltage drop should not be a concern.
> 
> Any suggestions?  Thanks,
> 
> Eric Youngren
> 
> [Non-text portions of this message have been
> removed]
> 
> - - - -
> To send a message: RE-wrenches at topica.com
> 
> Archive of previous messages:
> http://www.topica.com/lists/RE-wrenches/
> 
> List rules & etiquette:
> http://www.mrsharkey.com/wrenches/etiquete.htm
> 
> Check out participant bios:
> www.mrsharkey.com/wrenches/index.html
> 
> Hosted by Home Power magazine
> 
> Moderator: michael.welch at homepower.com
>
> 
> 


__________________________________
Do you Yahoo!?
Yahoo! SiteBuilder - Free, easy-to-use web site design software
http://sitebuilder.yahoo.com

- - - -
To send a message: RE-wrenches at topica.com

Archive of previous messages: http://www.topica.com/lists/RE-wrenches/

List rules & etiquette: http://www.mrsharkey.com/wrenches/etiquete.htm

Check out participant bios: www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine

Moderator: michael.welch at homepower.com
--^----------------------------------------------------------------
This email was sent to: michael_welch at sbcglobal.net

EASY UNSUBSCRIBE click here: http://topica.com/u/?bz8Qcs.bz9JC9.bWljaGFl
Or send an email to: RE-wrenches-unsubscribe at topica.com

TOPICA - Start your own email discussion group. FREE!
http://www.topica.com/partner/tag02/create/index2.html
--^----------------------------------------------------------------